It's hard to say. Other's bring up "city sieges" and talk about it as if it's something entirely new. It is, and it isn't. Age of Conan will be out May 20th, and "city sieges"(though unique compared to WAR's style) will be in at launch. Whereas WAR is going to be in Beta for quite some time. Hard to claim "first" there.

I think WAR will probably be remembered for being "that game"....not the one to trump WoW but the one to actually make Blizzard notice a decent loss in subscribers. This in turn could be great news for the WoW community as well, as Blizzard could jump into action trying to "steal some thunder", easily done by hijacking some of the easier translated ideas used in WAR that are causing it to be so popular.